With increasing demands and shrinking sizes of the consumer handheld electronics, there is a growing need to improve transistor performance. There are several ways of improving carrier mobility and, hence, transistor performance: using uniaxially strained silicon using tensile or compressive stressors; using biaxially strained silicon on relaxed silicon germanium virtual substrates; or using biaxially strained silicon on insulator. Transistors with silicon germanium source/drain regions have been demonstrated for mobility and drive current enhancement. However, this process induced stress engineering technique cannot be used in many secondary components like input/output and long channel transistors, drain extended metal oxide semiconductors (DEMOS), pnp transistors, etc. Furthermore, it has been established that shallow trench isolation regions generate compressive stress inside the active regions. This causes large mobility and drive current degradation for secondary active components.
Thus, there is a need to overcome these and other problems of the prior art and to provide methods of improving mobility and drive current for secondary active components in a CMOS device.